Expansion anchors are known from EP 0514342 A1, for example. They are inserted into a borehole in a substrate of a component, for example in a wall or a ceiling. By retracting an expansion cone, which has an inclined surface and which is provided on the bolt, into a anchor body designed as an expansion sleeve, this anchor body is radially expanded and pushed outwardly, thus anchoring the expansion anchor in the substrate. According to EP 0514342 A1, a friction-reducing coating is provided at the contact area between the expansion cone and the anchor body.
US 2008/0050195 A describes an expansion anchor in which the surface roughness of the expansion sleeve increases toward the rear end of the expansion anchor.
DE 4225869 A1 describes a anchor made of stainless steel, in which the anchor body is spread apart by tightening a screw or a nut, or by forcing into place an expansion body, and during the spreading operation two surfaces move toward one another with increasing compression, these surfaces subjected to the compression being provided with a coating that counteracts blocking, and for one of the surfaces subjected to the compression the coating being formed by galvanizing or nitriding, and an additional layer of lubricating lacquer, wax, or grease optionally being applied.
US 2009/0290953 A describes a screw with a double coating that includes an outer layer that may be rubbed off.